Vacuum pump again...maybe?

[mudder110]

hi all looks like the vacuum pump may have failed second one in 12 months
on my 300tdi defender its a allmakes.
the pedal stays hard when on idle seems to pullup ok, though what I am noticing is a rattle that comes and goes in pulses if that makes sense if I touch the accelerator it does not seem to get any louder but still there.
what would be the best way to check the vacuum pump?.
starting to feel like the old girl is falling to bits any help appreciated cheers.

[wrinklearthur]

It could be the vacuum pump, but first do a check on the end of the hose where it goes onto the booster. pull the hose off the elbow, then with the engine going at a fast idle put your thumb over it's end and you should feel the vacuum increasing.

If that is okay then I would be then checking for cracks in the metal around the booster canister.

If the end plate on the vacuum pump has come loose, the fix for that is; disassemble the plate from the body by drilling out the rivets, wash the parts checking the valves, then reassemble using small bolts and nylock nuts, to replace the rivets.

When re-installing the pump use two gaskets between the pump and the engine block.
.

[vnx205]

Cracks in the booster where the master cylinder bolts on are common enough that at least one supplier won't provide any warranty for the vacuum pump unless you replace the booster at the same time.

While there may be other reasons why vacuum pumps fail, a cracked booster seems to be a fairly common reason for regular, premature pump failure.

Definitely worth a close look at the booster.

[Bushie]

^ x 2

And don't buy an aftermarket booster , fell into that trap once when I couldn't lay my hands on a booster quickly - never got a good pedal

[ame="http://www.youtube.com/watch?v=wU3CyjTFiZ4"]booster1.avi - YouTube[/ame]
(Wonder why ) Don't think that booster would have lasted very long before cracking.


Martyn